Constantly increasing environmental awareness means that more and more waste materials which hitherto were normally dumped freely are now recognized as being harmful to the environment. For example it was conventional practice in the past to dump ashes from refuse incineration plants or from sewage sludge incineration as well as filter dusts in either storage areas which were specifically provided for that purpose, or on normal refuse dumps. However recent knowledge has shown that toxic substances such as heavy metals are washed out of such ashes and dusts during storage thereof by rain water, and become distributed in the water table.
The underlying object of the present invention was therefore that of providing a process for producing dumpable agglomerates of finely divided waste materials, in which a high degree of resistance to leaching out is achieved with the minimum amount of binding agent and thus at a minimum level of cost.